The conventional residential telephone set comprises a handset and a stand providing on its top a cradle for the handset. Included in the stand is a line switch and switchhook mechanism which usually comprises (a) vertically movable plungers passing from the cradle through holes in the stand's housing into its interior, and (b) a motion coupling linkage extending in such interior from the bottoms of the plungers to the switch and responsive to movement of the plungers between up and down positions therefor to shift contacts in the line switch means between open and closed conditions therefor. The operation of such mechanism is such that the weight of the handset in the cradle depresses the plungers to cause the mechanism to maintain the mentioned contact open or closed as appropriate for the ON-HOOK condition of the telephone set. When, however, the handset is lifted off the cradle, the removal of its weight from the plungers causes the mechanism to change the conditions of the contacts to that appropriate for the OFF-HOOK condition of the set, and for signaling the central office that the set is OFF-HOOK.
In the past, motion coupling linkages of the sort described above have tended to be complex in their action by virtue of converting the original simple vertical movement of the plungers into one or more other linkage movements differing in direction and magnitude from such original movement and from each other. Also such linkages have often had a large number of parts and have, on that account, been expensive.
Additionally, since such mechanisms are housed in telephone housings, wherein as a rule sufficient space is available for locating the mechanisms, the overall size of the mechanisms tends to be on the bulky side.
While the characteristics of complexity and high cost of the mechanisms are significant disadvantages for use in telephone sets, the size of such mechanisms makes it virtually impossible to incorporate such mechanisms in handset cradles which extend from a side of a telephone set or a communications terminal, and especially so when design requirements are such that from the aesthetic standpoint the handset cradle has to be as slim as possible and from the reliability standpoint it has to be strong enough to serve as a handhold to be used by an operator to move the phone or the terminal.